Research And Realization Of High Reliable Embedded Operating System Kernel

With the progress of information technology,complex embedded real-time systems are more widely used in many industrial, avionics, consumer products, information appliance and military applications. New domains and application especially the safety critical systems raise many new requirements towards embedded real-time operating system. The most important features include high real-time performance, reliability and security. Many foreign researchers are working on those problems now, but there is few relevant research inland. So It's valuable and important to deeply investigate, study and develop the high reliability embedded real-time operating system ourselves.Good operating system architecture can optimize the critical performance of the system. Moreover, It can balance other performance requirement of the operating system and guarantee the realization of the design goal of the operating system. In the second chapter,we analyze the mainstream operating system architecture at present and their strength and weakness in detail, and further investigate the feasibility and methods of constructing the real-time operating system using the object-oriented technology and component technology. We also discuss the critical problem on designing and realizing the multiprocessor real-time operating system in this chapter. On basis of this, we present an object-based multiprocessor real-time operating system architecture, which is combined with the micro-kernel model and the layered model,and apply it to the design of CRTOS II.Strong reliability guarantee is the necessary condition to apply embedded real-time operating system to the safety critical system. In the third chapter, we analyze and investigate the reliability guarantee technology of the embedded real-time operating system, from the point of the real-time kernel reliability, the space- temporal isolation protection technology, security and safety.Generally we can improve the real-time kernel reliability through following three aspects. First, introduce the fault-tolerant real-time schedule algorithm to support fault tolerant in system, through the reasonable resource reserve strategy. Second, Adopting the micro-kernel and layered operating system structure was in favor of improving the reliability and maintainability of the code. At last, identify and dispose the latent problems to strengthen the reliability of the system, by improving the error processing mechanism of the real-time kernel itself. This paperinvestigates the fault-tolerant real-time schedule algorithm deeply ,then presents two new fault-tolerant real-time scheduling algorithms based on checkpointing scheme CP-PRA and CP-FTRM,and applies it to the design of CRTOSII.The processor and memory are two most important kinds of resource. The space- temporal isolation mechanism tries to downgrade the dependence of the tasks through introducing the means of address space isolation processor isolaion, memory quota system. It constrains the error within limits, and improves the dependability of the system. This paper presents a unified space- temporal isolation mechanism, in advantage of the concept of the "protection domain", and applies it to the design of CRTOS II.Finally this paper investigates the critical technology of the implementation of the embedded real-time kernel. Based on this, we design and implement a kernel of the multiprocessor real-time operating system-CRTOS II. Through the preliminary test, the result show CRTOS II has good real-time performance.